INTRODUCTION	Section 2 of 10
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Background: The causes of pure tricuspid regurgitation are multiple, and this lesion is the fifth most frequently excised native cardiac valve in patients older than 15 years. Tricuspid regurgitation may result from structural alterations of any one or all of the components of the tricuspid valve apparatus. Components include the leaflets, chordae tendinea, annulus, and papillary muscles or adjacent right ventricular (RV) muscle. The lesion may be classified as primary when it is caused by an intrinsic abnormality of the valve apparatus or as secondary when it is caused by RV pressure or volume overload.

Pathophysiology: The pathophysiology of tricuspid regurgitation focuses on the structural incompetence of the valve. The incompetent nature of the valve can result from primary structural abnormalities of the leaflets and chordae or from secondary myocardial dysfunction and dilatation.

Tricuspid valve insufficiency is generally found in combination with tricuspid stenosis. The most common cause of this problem appears to be rheumatic in origin. Ebstein anomaly accounts for the most common congenital form of this abnormality.

In tricuspid regurgitation, chronic right atrial overload results in right-sided congestive heart failure (CHF) manifested by hepatic congestion, peripheral edema, and ascites. Because of the impedance of flow to the pulmonary vasculature, hypoxemia, cyanosis, and polycythemia may result.

Frequency:

• In the US: Incidence of tricuspid regurgitation appears to be 0.9%.

• Internationally: Incidence of tricuspid regurgitation appears to be less than 1%.

Mortality/Morbidity: The morbidity and mortality of the disease process are secondary to the underlying cause. In rheumatic disease, mortality rates with treatment are less than 3%. In Ebstein anomaly, mortality depends upon the severity of the deformity and the feasibility of correction. Mortality rates with correction are approximately 10%. Tricuspid regurgitation resulting from myocardial dysfunction or dilatation has a mortality rate of up to 50% at 5 years.

Race: No race predilection is apparent.

Sex: No sex predilection is apparent.

Age: Ebstein anomaly can be detected at birth and during early childhood. In patients older than 15 years, the most common form of tricuspid regurgitation is rheumatic valvular disease. In the adult population, other predisposing factors, including carcinoid, bacterial endocarditis, and CHF, take precedence.

	CLINICAL	Section 3 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

History: The patient with tricuspid regurgitation presents with the signs and symptoms of right-sided heart failure. The spectrum of presenting symptoms is dependent upon whether the condition is secondary to left ventricular (LV) dysfunction. If it is, dyspnea on exertion and paroxysmal nocturnal dyspnea accompany ascites and peripheral edema as common presenting complaints. Exercise intolerance and hypoxemia may also be observed. The patient rarely reports angina, which may be present in the absence of coronary artery disease secondary to RV overload and strain.

These patients must be questioned regarding drug use and history of rheumatic fever and febrile episodes because bacterial endocarditis is a common cause of tricuspid valvular disease.

Physical: S₃ gallop is present, and the following physical findings may be found:

• Jugular venous distention with a prominent V wave: When present, a pansystolic murmur is heard along the lower left sternal border with inspiratory accentuation.

• Diminished peripheral pulse volume secondary to impaired forward blood flow: Patients with this sign may have relative hypotension secondary to therapeutic interventions used to decrease volume overload.

• Pulmonary rales associated with LV dysfunction or mitral stenosis

• RV heave and gallop that increases with inspiration

• Ascites

• Peripheral edema

• Cachexia, cyanosis, and jaundice

• Atrial fibrillation

• A high-pitched pansystolic murmur (loudest in the fourth intercostal space in the parasternal region): The murmur is usually augmented during inspiration and is reduced in intensity and duration in the standing position and during a Valsalva maneuver. A short, early diastolic flow rumble may be present.

Causes: Pure tricuspid regurgitation can be caused by at least 9 conditions.

• Rheumatic heart disease

• Tricuspid regurgitation secondary to rheumatic involvement is usually associated with mitral valve pathology.

• The valve develops diffuse fibrous thickening without commisural fusion, fused chordae, or calcific deposits.

• Occasionally, the chordae may be mildly thickened by fibrous tissue. Rheumatic disease is the most common cause of pure tricuspid regurgitation due to deformation of the leaflets.

• Endocarditis

• This is an important cause of pure tricuspid regurgitation. Precipitating factors that can contribute to infection of the valve include alcoholism, opiate addiction, neoplasms, infected indwelling catheters, extensive burns, and hereditary immune deficiency disease.

• The clinical presentation is that of pneumonia from septic emboli rather than CHF. Heart murmurs are frequently absent. Annular abscesses are not uncommon.

• Ebstein anomaly

• This entity is a congenital malformation of the tricuspid valve characterized by annular insertion of the septal and posterior leaflets displaced apically and atrialization of a portion of the ventricular myocardium.

• Prognosis for these patients depends upon the degree of apical displacement of the tricuspid annulus and the severity of the regurgitation.

• Prolapse (floppy, redundant)

• The incidence of floppy tricuspid valve varies from 0.3-3.2%.

• The lesion appears to be associated with prolapse of the mitral valve and does not appear to occur in an isolated fashion.

• Histological examination of the floppy tricuspid valve shows alterations on the valve spongiosa.

• Carcinoid

• Pure tricuspid regurgitation can occur as part of the carcinoid heart syndrome.

• Fibrous white plaques form on the ventricular aspect of the tricuspid valve and endocardium, causing the valve to adhere to the RV wall.

• Proper systolic coaptation does not occur, resulting in tricuspid regurgitation.

• Papillary muscle dysfunction

• Papillary muscle dysfunction may result from necrosis (secondary to myocardial infarction), fibrosis, or infiltrative processes.

• Although dysfunction secondary to myocardial infarction is less common than the same pathology observed with the mitral valve, the underlying cause must be determined in order to plan treatment.

• Trauma
  • Occasionally, trauma to the right ventricle may damage the structures of the tricuspid valve, resulting in insufficiency of the structure.

  • More commonly associated with stab wounds, projectile destruction of the valve can also occur.

• Connective-tissue diseases
  • Patients with Marfan syndrome or other connective-tissue diseases (eg, osteogenesis imperfecta, Ehlers-Danlos syndrome) may have pure tricuspid regurgitation.

  • Other valvular dysfunction is also observed in the same patient.

  • The etiology of the regurgitation can be attributed to a floppy tricuspid valve and a mildly dilated tricuspid valve annulus.

• Anatomically normal tricuspid valves

• A common etiology of tricuspid regurgitation is dilatation of the RV cavity.

• The valve structures are normal; however, because of enlargement of the cavity and dilatation of the annulus, proper coaptation of the leaflets is not possible.

• Causes of the dilatation include mitral stenosis, pulmonic stenosis, pulmonary hypertension, dilated cardiomyopathy, and RV failure.